1. Field of the Invention
The present invention relates to an electrophotographic fixing member. The present invention also relates to a fixing apparatus and an electrophotographic image forming apparatus using the member.
2. Description of the Related Art
In general, in a heat-fixing apparatus for use in an electrophotographic system such as a laser printer or a copier, rotation members such as a pair of a heated roller and a roller, a film and a roller, a belt and a roller, and a belt and a belt are in pressure-contact with each other.
Then, a material to be recorded, which holds an image by an unfixed toner, is introduced to a pressure-contact portion (fixing nip) formed between the rotation members, and heated, and thus the toner is molten to fix the image to the material to be recorded such as paper.
The rotation member with which the unfixed toner image held on the material to be recorded is in contact is referred to as a fixing member, and is called a fixing roller, a fixing film or a fixing belt depending on the form thereof.
As such fixing members, those having the following configuration are known.
A configuration in which a substrate formed of a metal, a heat resistant resin or the like is covered with a silicone rubber elastic layer having heat resistance and a releasing layer made of a fluororesin, the layers sandwiching a silicone rubber adhesive therebetween.
A configuration in which a releasing layer is formed by forming a coat of a coating material including a fluororesin on a silicone rubber elastic layer and firing the coat at a temperature equal to or higher than the melting point of the fluororesin.
The fixing member having such a configuration can enclose and melt a toner image in the fixing nip without excessively compressing the toner image, with the use of an excellent elastic deformation of the silicone rubber elastic layer. Therefore, the fixing member has an effect of preventing image displacement and bleeding, and improving color mixing in particular when fixing a color image of multicolor construction. The fixing member also has an effect of following the irregularities of fibers of paper as the material to be recorded, to prevent the occurrence of melting unevenness of toner.
Furthermore, the function of the fixing member is demanded to supply to a material to be recorded a sufficient amount of heat for instantaneously melting a toner in a fixing nip portion.
Against such a problem, a configuration in Japanese Patent Application Laid-Open No. 2004-45851 is known in which a high heat capacity material is incorporated to a part of a fixing member to allow the fixing member to ensure a high heat capacity, resulting in the increase in amount of heat supplied to the material to be recorded. Since a larger amount of heat can be thus stored in the fixing member, the configuration is considered to be effective for electric power saving and an increase in speed.
In addition, in Japanese Patent Application Laid-Open No. 2002-268423, a fixing belt has been proposed in which carbon fibers formed by a vapor growth method are contained in an elastic layer to thereby improve the heat conductivity of the elastic layer. In addition, the present inventors have proposed a heat-fixing member in which carbon fibers, and an orientation inhibitory component of the carbon fibers, such as silica, alumina or iron oxide are contained in an elastic layer to thereby improve the heat conductivity of the elastic layer in the thickness direction (Japanese Patent Application Laid-Open No. 2006-259712).